For me, megawatt laser weapons that somehow don't bloom are a must for 6th gen.
If you have lasers you won't need fast speeds or AI team ups or any of the other not so new crap. We have heard NGAD broke SR71's records but I suspect it was for mere seconds. Considering how fuel hungry ramjets are.
AI will not outsmart humans anytime soon.
That leaves us with my fav, laser weapons! Both for air combat and ground attacks. Yes, yes, I know... No way a jet engine can possibly power a megawatt laser, or a fighter jet can possibly carry it etc. etc. But still until laser weapons on planes become real everything else will still be only 5+ gen IMHO.